A compressor unit is known from U.S. Pat. No. 3,960,468, which discloses a compressor unit for compressing a gas. The compressor unit comprises a centrifugal compressor and an electric motor. The electric motor comprises a stator and a rotor, the rotor driving the compressor. The compressor and the electric motor are accommodated in a common gastight housing which is provided with a gas inlet and a gas outlet.
In the compressor unit shown in FIG. 1 of U.S. Pat. No. 3,960,468, there is a thin partition between the space in which the stator is located and the space in which the rotor is located. A partition of this type ensures that any aggressive substances which may be present in the gas which is to be compressed cannot reach the stator space, where they could attack the stator. This known partition is thin and may be made from a metal with a high electrical resistance or from a nonconductive material. As can be seen from FIG. 1, the known partition is supported on the stator.
The known partition has various drawbacks. Firstly, the partition may cause wear to itself and to the stator. Wear of this type occurs when the partition and the stator move with respect to one another as a result of fluctuating pressures and/or temperatures. Secondly, the known partition is unable to absorb high pressure differences between the stator space and the rotor space. To the extent that the partition is able to absorb pressure differences, this is attributable to the support on the stator, and not to the properties of the partition itself.